Question

If \[x ^{2}-xy+y ^{2} = a\] and \[x ^{3} + y ^{3} = b\] then xy = ?

Answer 1

use a^3+b^3 formula to find out the value of x+y first.

Answer 2

\[x ^{3} + y^{3} = (x + y)(x^{2}-xy+y^{2})\]
b = (x +y) (a)
b/a = x + y

Answer 3

\[xy=\frac{b^2-a^4}{3a^2}\]

Answer 4

sorry

Answer 5

\[xy=\frac{b^2-a^3}{3a}\]

Answer 6

square x+y

put the values of x^2+y^2 from your first equation.

Answer 7

sorry it is wrong again..

Answer 8

\[xy=\frac{b^2-a^3}{3a^2}\]

Answer 9

take the sq of last eq. you found..

Answer 10

so its x^2 + y^2 = b^2/a^2 - 2x .. im trying lol

Answer 11

\[\frac{b^2}{a^2}=x^2+2xy+y^2\]

Answer 12

wait ill try to see my answer then ill compare it to cinar

Answer 13

\[x^2+y^2=a+xy\]

Answer 14

\[\frac{b^2}{a^2}=a+3xy\]
\[\frac{b^2}{a^2}-a=3xy\]

Answer 15

thanks

Answer 16

yw